Adding HDMI 2.0 into GCN for the Nano would have required a time machine and adding several dollars to the BOM. AMD was far too deep in designing Fiji by the time the HDMI 2.0 specification was close to finished. Current implementations on Maxwell, to my knowledge, don't support the latest versions of HDCP fully, either. So neither company is completely on board with HDMI 2.0 support.
Adding HDMI 2.0 to GCN? I think you might be confused, GCN is the 3D geometry and rasterizer architecture used in the actual rendering engine of the GPU, and as such, it doesn't handle the display interface the video card will utilize to connect to a particular monitor or TV, this is a separate part in the overall architecture of a video card, and as explained before (or even suggested by certain people) is a limitation that could be "easily" overcome by utilizing a DP to HDMI adapter or, in the case of having this feature enabled out of the box for this card in particular, by adding a converter chip such as the ones utilized in said converters between the actual GPU and the display interface connector, no need to mess with the architecture inside the GPU itself.
What you're saying is akin to proposing GCN is incapable of rendering HDMI 2.0 because its rendering engine cannot output a game at 3840x2160 and 60 frames per second, something we know this card is very capable of, one thing is not related to the other.
Also, I want to bring to your attention the fact that the HDMI 2.0 protocol was finalized as such in September of 2013, a full two years ahead of the release of the Nano.
As for HDCP 2.2, once again, I believe you might be confused about the real purpose of this especification, which refers to the ability of your video card to display protected content using HDCP 2.2 protocol. This has absolutely nothing to do with the ability of your video card to be able to display games to any given 4K display at 60Hz, in fact, as of Sept 2015, there's no content available that utilizes this protection protocol, and it is expected that by this holiday season, the first UHD bluray movies or HDR enabled content that will require the use of this protocol will be released, which as mentioned before, is only utilized for protected media content, and not for gaming.
Also, you are not correct in saying neither Nvidia, nor AMD are completely on board with HDMI 2.0, in fact Maxwell based 960 and 950 cards fully support HDCP 2.2, as well as the IGP found in Intel's Skylake processors, Nvidia has said they'll tentatively enable this feature to more of their Maxwell based GPUs as more protected content media is released next year, whether this is true or not, is not even pertinent to the topic we are discussing.
Hope this helps clear up some of your doubts, in reality, I think this topic should be dropped already, as it seems we are going in circles, and I'm sure, the majority of our forum members must be tired of the ongoing debate, and of the constant derailing of the original purpose of this review and its thread.
Truth is Nano is a very nice card, in fact, there's nothing out there quite like it, and I don't believe the green team expected this card to even exist, and I can't think of how their engineering team will respond to it, as I think they got caught with their pants down
It's such a shame that a few features were not included by AMD, which would have truly made this card shine in certain situations; also, in my personal opinion, the decision to price the card as they did, only opened them to further criticism when you take into consideration that for $650, Fury X is a much better card.
From my opinion the Nano x 2 is Expensive but if your cashed up and love gaming its a good option
